This invention relates to apparatus for removably mounting one or more ink cartridges within a carriage for reciprocally moving the cartridge of a small ink jet printer through the printing station of a machine.
In particular, this invention relates to a latching mechanism for removably securing one or more ink cartridges in the carriage of a small point of sale type printer. Many of the devices for securing an ink cartridge in a carriage involves lever and spring mechanisms that are relatively large and complex devices. As a consequence, these devices consume a good deal of valuable space and leave little room for the user to operate the mechanism during insertion and removal of the cartridge. It should be further noted that many of these prior art devices are arranged so that they bear directly upon the back wall of the cartridge when the cartridge is latched within the carrier. The cartridge is typically constructed of a thin material such as plastic and the holding force of the latching device can deform the cartridge forcing ink from the nozzles. This, in turn, produces unwanted dirt problems within the printer which, in extreme cases, requires the machine to be taken out of service for cleaning.
By the same token, if the latching mechanism does not hold the cartridge securely within the carrier, there is a high probability that the electrical connector located upon the front face of the cartridge will not make positive contact with the input terminals located on the opposing front wall of the carrier. When this occurs, the printer will produce a faulty or unintelligible printout.
As disclosed in U.S. Pat. No. 4,709,247, some latching devices require specially configured ink cartridges to insure proper engagement and operation of the latching mechanism. The cost of the ink cartridge is therefore substantially higher than the less complex cartridges presently in the market and therefore, reliability is generally lessened due to the close tolerances between parts.